refactor: update token generation method and improve maxSessions validation

- Changed the token generation method to use slice instead of substr for better readability.
- Enhanced maxSessions validation in the settings update handler to check for undefined values and ensure the input is a number before processing.

apps/server/src/routes/terminal/common.ts

@@ -54,7 +54,7 @@ export function getTokenData(
 export function generateToken(): string {
   return `term-${Date.now()}-${Math.random()
     .toString(36)
-    .substr(2, 15)}${Math.random().toString(36).substr(2, 15)}`;
+    .slice(2, 17)}${Math.random().toString(36).slice(2, 17)}`;
 }
 
 /**

apps/server/src/routes/terminal/routes/settings.ts

@@ -25,7 +25,15 @@ export function createSettingsUpdateHandler() {
       const terminalService = getTerminalService();
       const { maxSessions } = req.body;
 
-      if (typeof maxSessions === "number") {
+      // Validate maxSessions if provided
+      if (maxSessions !== undefined) {
+        if (typeof maxSessions !== "number") {
+          res.status(400).json({
+            success: false,
+            error: "maxSessions must be a number",
+          });
+          return;
+        }
         if (!Number.isInteger(maxSessions)) {
           res.status(400).json({
             success: false,

apps/server/src/services/terminal-service.ts

@@ -233,7 +233,7 @@ export class TerminalService extends EventEmitter {
       return null;
     }
 
-    const id = `term-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
+    const id = `term-${Date.now()}-${Math.random().toString(36).slice(2, 11)}`;
 
     const { shell: detectedShell, args: shellArgs } = this.detectShell();
     const shell = options.shell || detectedShell;